FR2557218A1 - HYDRAULIC REMOTE CONTROL TRANSMITTER WITH FLOW AMPLIFIERS - Google Patents

Abstract

THE INVENTION CONCERNS A DEVICE FOR THE CONTROL OF SEVERAL HYDRAULIC CIRCUITS. THE SWING LEVER 1 ACTIVATES SEVERAL CONTROL PISTONS 3 OF THE CONTROL STAGE 5. EACH OF THEM ACTIVATES ONE OF THE PISTONS 21 OF THE POWER STAGE 6, CONNECTED BY THE HYDRAULIC CHAMBERS 26 TO THE APPLIANCES. EACH CONTROL PISTON 3 DEFINES A HYDRAULIC POTENTIOMETER WITH CONICAL TRANSITION SURFACES 16, 17. APPLICATIONS: MULTIPLE HYDRAULIC CONTROLS, ESPECIALLY FOR PUBLIC WORKS EQUIPMENT.

Description

This intention relates to an issuer

  hydraulic remote control unit, equipped with

positive flow amplifiers.

  It is known that, on a remote control hydraulic circuit, the user activates a lever or a keyboard, which triggers the desired commutations.

  in a hydraulic circuit that also actuates

  Such receivers are most often

  consisting of cylinders or hydraulic motors

  They can be more or less distant from the control station. Most of the devices known to date have various drawbacks, among which: the hydraulic flow rate sent to the devices of use

  is relatively small, so the pre-installation

  feels too much response time;

  - the flow of regulation makes an important contribution of

  lories, this yes leads to an exaggerated warm-up;

  - even important. the regulation flow is not sufficient

  to reduce the response time of the facility as much as - the flow on the use of the potentiometer disturbs the

  characteristic curve of the latter.

  The present invention aims to avoid these disadvantages, which is particularly significant

  particularly on the hydraulic circuit used for the

  public works machinery or heavy vehicles.

  A hydraulic control transmitter

  according to the invention, is characterized in that

  door at least two stages, namely: - a control stage, in which slide pistons operating according to the known principle of the hydraulic potentiometer; a power stage, or amplification stage, in which

  slide dispensing pistons, connected to

  the rules of use to which they

  hydraulic flow rates of power and

tion.

  According to another characteristic of the in-

  vention, each piston of the potentiometric stage of com-

J557218

  mande is in the form of a cylindrical drawer whose narrowed central portion has the general shape of a diabolo, that is to say that the small central section is connected by frustoconical transition zones to both

  cylindrical ends of the drawer.

  According to another characteristic of the in-

  vention, the central area with narrowed section of a piston

  has an opening that communicates with a long canal

  dinal provided inside this piston to open on one of its ends, directed to a corresponding piston

  the power stage or amplifier stage.

  The attached drawing, given as an example

  non-limitative, will provide a better understanding of the

of the invention.

  Figure 1 is a schematic sectional view

  of a control station equipped according to the invention.

  tion, with two superimposed hydraulic stages.

  Figures 2 to 4 are longitudinal sections

  nales illustrating the operation of a piston of the floor

  control, or potentiometric stage.

  Figures 5 to 7 are longitudinal sections

  nales illustrating the operation of a piston of the floor

  power amplifier, or amplifier stage.

  Figure 8 is a diagram illustrating the principle

  operation of the potentiometric stage.

  Figure 9 shows the characteristic curve

  resulting, for the control stage.

  There is shown in the drawings a control box of the type that exists for example on public works machinery. This boftier is surmounted by an oscillating control lever 1, whose base

  is equipped with a thrust plate 2. During oscilla-

  lever 2, the plate 2 comes to push more or less one or two movable control pistons 3 against return springs 4

  According to the invention, the control pistons

  of 3 slides inside a block which constitutes a

  Command 5, while below it is

find a power stage 6.

  The control stage 5 comprises sliding pistons 3, each of which operates according to the known principle of the hydraulic potentiometer. In other words, each piston 3 comprises a narrowed section 7 disposed between two cylindrical portions 8 and 9. It slides in the direction indicated by the double arrow 10, to move in front of three grooves of the stator, namely: - a central control groove 11

  a pressure supply groove 12 connected to the central

  the feed hydraulics 13; a return groove 14, connected to the return circuit 15

hydraulic installation.

  According to the invention, two frustoconical zones

  transitions 16 and 17 are arranged between the section

  7 and respectively the cylindrical portions 8 and 9, which ensures a great progressiveness to the operation of the

hydraulic potentiometer.

  On the other hand, the narrowed section 7 communicates with an opening 18, with an axial passage 19 of the piston 3. This axial bore 19 opens into the corresponding part of the power stage 6 O.

  Particularly the chamber 20 actuating the head of a pis-

  Power Tone 21 Each power piston 21 slides in the stator of the power stage 6, which comprises - a groove 22 connected to the hydraulic return circuit 23 - a power supply throat 24, connected to the hydraulic power station of power 25; an end chamber 26 connected directly to the use circuit, ie to the receiving apparatus

  (motors or cylinders) of the installation.

  Each power piston 21 slides by cylindrical sealing surfaces between which is defined a narrowed section 27. This communicates through an orifice 28 with an axial channel 29 which passes through it for

  open into the chamber of use 26.

  Each operation piston 3 defines with the various bores separating the grooves 11, 12, 14, variable restrictions depending on the displacement of the piston.

  piston 3. When, through the oscillating lever

  lant 1, the operator moves a piston 3 against the action of its return spring 4, it connects the corresponding pressure groove 12, with the control groove I1 and

  the return throat 14. The connection between the feed throats

  tation 12, and control it, is carried out by a choke-

  whose ring section is defined as a function of the position of the transition cone 16. Similarly, the connection between the return groove 14 and the control groove 11 is made by a constriction whose annular section depends on

  the position of the conical transition zone 17.

  Thus, we define the equivalent of a

  inlet nozzle 30, with a variable section, between the groove 12 and the chamber 20, and the equivalent of an outlet nozzle 31

  also variable section, between the chamber 20 and the gor-

  Return 14. A hydraulic potentiometer has been realized.

  whose schematic representation is given at the end of

8.

  From a supply source 12, 13, at constant pressure, there is therefore a control pressure which is between zero and the nominal value.

  12. The variation of this pressure

  control voltage Pc depending on the displacement of the piston of

  command 3 (or the angle o (of lever 1), is

shown in Figure 9.

  Note that it is possible to obtain

  for the graph in Figure 9, all forms of

  besides, by defining the construction dimensions and

  forms of the generatrices of the conical parts 16, 17.

  When the control stage 5 sends

  the control pressure in the chamber 20 of a piston of use

  21, it moves and establishes the link between

  be the pressure groove 24, and the chamber of use 26.

  this connection is maintained as long as the control pressure

  Pc in the control chamber 20 is greater than the pres-

  This connection is maintained as long as Pu (chamber 26) remains

greater than Pc (chamber 20).

  If Pu tends to be greater than PC, the piston 21 moves and cuts the connection between the chambers 24 and 26. If this pressure P continues to rise the piston 21 moves again and establishes the connection between the chamber of use, and the return groove 22, until the equal equilibrium of the two pressures Pu and P c is found again. When the control (stage) is released, the piston 3 resumes its rest position * and the pressure control in the chamber 20 vanishes. Thus X the corresponding use piston 21 resumes its position

  resting place (Figure 7), for which the pressure of

  in room 26 is canceled by placing in communication

with the return throat 22.

  The device that has just been described has the following advantages in particular:

  the low flow required to control the amplifier stage

  This indicator does not disturb the regulatory curve.

  their it allows to seriously reduce the flow of regu--

  2 fation of the potentiometer, therefore the intake of calories; - the amplifier or power stage is not limited

  flow through the constrictions, as in the potentio-

  meter, allows the passage of a large flow, therefore sup-

press.on response times.

r-

Claims (4)

  1 - remote control hydraulic transmitter, characterized in that it comprises at least two stages, namely:   a control stage (5) in which pistons slide   (3) operating according to the known principle of   hydraulic tiometer; a power stage (6) or amplification stage, in which   10 slide dispensing pistons (21) connected to   these uses to which they   change in the hydraulic flows of power and   tion. 2 - hydraulic transmitter according to claim 1, characterized in that each piston (3) of the potentiometric control stage is in the form of a cylindrical spool (8). (9), whose narrowed central portion has the general shape of a diabolo,   that is, the small central section (7) is connected   by frustoconical transition zones <16), (17)   two cylindrical ends (8) (9) of the drawer (3).   3 - Hydraulic transmitter according to one   any of the preceding claims, characterized in that   the narrowed-section central zone (7) of a piston (3) has an opening (18) which communicates with a longitudinal channel (19) provided inside the piston (3) to open on one from its ends in a control chamber (20) directed towards a corresponding piston (21)   the power stage or amplifier stage (6).   4 - Hydraulic transmitter according to the   claim 3, characterized in that each piston of com-   mande (3) of the control stage (5) is located in the extension of a use piston (21) of the stage of   power (6), so that the power stage (6) is   in the form of an insert block against the block of the control stage (5) at the end of the control lever (1) from the whole.